CVE-2017-17850
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered in Asterisk 13.18.4 and older, 14.7.4 and older, 15.1.4 and older, and 13.18-cert1 and older. A select set of SIP messages create a dialog in Asterisk. Those SIP messages must contain a contact header. For those messages, if the header was not present and the PJSIP channel driver was used, Asterisk would crash. The severity of this vulnerability is somewhat mitigated if authentication is enabled. If authentication is enabled, a user would have to first be authorized before reaching the crash point.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe PJSIP channel driver in Asterisk crashes when processing SIP messages that create dialogs (INVITE, SUBSCRIBE, etc.) without a required Contact header. This causes a denial of service condition due to a null pointer or missing validation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 13.0.0, <= 13.18.4>= 14.0.0, <= 14.7.4>= 15.0.0, <= 15.1.4= 13.1.0= 13.8CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Asterisk versionRun 'asterisk -V' or 'asterisk -x "core show version"' to retrieve the installed Asterisk versionAffected if The version falls within 13.0.0-13.18.4, 14.0.0-14.7.4, 15.0.0-15.1.4 for Digium Asterisk, or 13.1.0/13.8 for Digium Certified Asterisk
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Confirm PJSIP is loadedRun 'module show like pjsip' to list loaded PJSIP modulesAffected if PJSIP modules are loaded and running
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Check active channel driverRun 'pjsip show version' or inspect /etc/asterisk/pjsip.conf to confirm the PJSIP channel driver is enabledAffected if PJSIP (chan_pjsip) is configured as an active channel driver
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Verify PJSIP endpoint or trunk configurationRun 'pjsip show endpoints' to list configured PJSIP endpoints, or review pjsip.conf for endpoint definitionsAffected if PJSIP endpoints or trunks are configured and active
You are affected if your Asterisk version is within the vulnerable ranges AND PJSIP is actively configured as a channel driver handling SIP dialogs (INVITE, SUBSCRIBE) without requiring authentication.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataEnable SIP authentication in PJSIP to require authorization before reaching the vulnerable code path, or upgrade to Asterisk versions 13.18.5, 14.7.5, 15.1.5 or later.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-17850 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2017-17850 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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